In a sysplex computing system, a coupling facility works like a common specialized system shared between operating systems. The coupling facility is a computer, and can fail. Accordingly, the sysplex includes a second (redundant) coupling facility. The first coupling facility (CF1) and the second coupling facility (CF2) can operate in duplex mode during which a command sent from an application to the CF1 is also sent to the CF2.
Conventional sysplex architectures require that the CF1 and the CF2 communicate with each other to ensure that both completed the command before the CF1 responds to the process that sent the command to the CF1. That is, the coupling works in a synchronous manner where the application has to wait for the backup CF2 to complete before receiving a response. This delay causes inefficiencies and overall system latency issues. In addition, a failure of a coupling facility that contains various structures requires significant recovery actions to be taken by the owning applications. For example, for database caches and queues, this may require using backup log data sets and/or tapes. Other structures, such as lock tables stored in the structure of a failed coupling facility, may require reconstruction of partial lock tables from in-storage copies along with failures of in-flight transactions.